1. Field of the Invention
The present invention generally relates to a method for treating oncological diseases by administering an agent that destroys extracellular DNA in the blood of a cancer patient.
2. Description of the Background Art
Populations of tumor cells developing in patients have a very high genetic variability which exceeds a same for healthy cells. Genetic variability of cancer cell populations causes mutated cells to generate phenotypes that (1) are insensitive to immune and morphogenetic control, (2) have an ability to invade and metastasize, and (3) are desensitized to cancer therapies. Selection and clonal expansion of cancer cells are both considered to underlie a biological and a clinical progression of tumors. For this reason, an approach of modern cancer therapies is based on a destruction of cancer cell clones in patients by means of chemotherapy, immunotherapy, biotherapy, surgical methods, or a combination thereof.
Chemotherapy, radiotherapy, biotherapy and more recent immunotherapy are the most commonly used non-surgical methods of treating cancer diseases. These therapies are administered to destruct, to damage or to inactivate a cancer cell's intracellular DNA.
The chemotherapy approach is based on administration of well known compounds: platinum preparations, antracycline antibiotics, alkylating agents and podophyllotoxins. The radioimmunotherapy approach is based on irradiation of intracellular DNA of cancer cells' nuclei. Alpha particles from alpha emitters are specially delivered into the cancerous cells to increase effects on those cells' intracellular DNA. Biotherapeutic and immunotherapeutic approaches are based on an induction of apoptosis of cancer cells, which induces death of the cancer cell. Apoptosis starts with an activation of intracellular nucleuses and follows with a degradation of the tumor cell's intracellular DNA. This process is accomplished, for example, by means of administering genotherapeutic constructions that consist of genes that induce apoptosis or genes coding the factors which activate the nucleuses.
Aguilera. et al. discloses in U.S. Pat. No. 6,455,250 endonuclease Endo SR to treat cancer diseases by mode of its intracellular delivery into target cells. This method and chemotherapy, with Etopozide-4-Demetilpipodophylotoxe (4,6-O—R)-etiliden-b-D-glycopiranozid, were both selected for a prototype of the present invention.
Topoizomeraze II is an essential cell enzyme that regulates many aspects of DNA function. The enzyme is responsible for interconversion of different topological forms of intracellular DNA by means of a generation of transitory breaks of double-stranded DNA. Etopozide, as a Topoizomeraze II inhibitor, increases an intracellular level of “broken DNA-Topoizomeraze II” complexes.
The result of this drug's influence is an accumulation of double-stranded intracellular DNA breaks which lead to the cell's death. A drawback of this method prototype, along with well-known methods, is their low efficacy. These methods imply that mostly the cancer cells' intracellular DNA is the therapeutic target. Because of high genetic variability, these cancer cells become desensitized to the therapies before they are adequately eliminated. A further disadvantage is that the intracellular DNA is a difficult-to-approach target; it leads to necessary high-dosing antineoplastic chemotherapy and/or other complicated delivery systems. A final disadvantage to these methods is that they are highly toxic: their influence on cancerous cells' intracellular DNA also damages healthy cells' DNA.